Bifidobacteria (or bacteria belonging to the Bifidobacterium genus) constitute one of the most important populations of human and animal faecal flora. It is generally considered an indication of good health when these bacteria are present at a high rate in faecal flora. For this reason, they are known as probiotic bacteria (beneficial microorganisms which improve the natural balance of intestinal flora when ingested alive). Examples of known Bifidobacteria include B. adolescentis, B. animalis, B. bifidum, B. breve, B. catenulatum and B. longum and these bacteria have been shown to have beneficial technological, organoleptic and probiotic effects.
Bifidobacteria are most commonly found as an additive in fermented milks (yoghurts with “active Bifidus”) and thus constitute an economically important commodity. The strains chosen by the milk industry must meet numerous strict requirements, such as resistance to the process of manufacture and survival within the foodstuff. The most commonly used species in France are B. animalis subsp. lactis and B. animalis subsp. animalis, which is a subspecies from animal origin, never isolated from humans. In view of the importance of bifidobacteria, there is a great need to identify novel species within this genus having properties optimally matched to the requirements of the food industry. For example, in 2004, a group identified and isolated Bifidobacterium psychraerophilum from a porcine caecum (Simpson, P. J. et al. (2004) Int J Syst Evol Microbiol 54: 401-6). Previously known Bifidobacterium species had only been able to grow at temperatures between 20° C. and 46-49.5° C. (Biavati, B. et al., (2000), Annals of Microbiology 50: 117-131; Dong et al., (2000) Int J Syst Evol Microbiol 50 Pt 1: 119-25), however, this bacterium demonstrated an advantage over all previous species by growing at between 4 and 10° C. This is beneficial for probiotic compositions as the bacteria are more likely to survive the low storage temperatures and would therefore prolong shelf-life. There is thus a great need for the identification of further bifidobacterial species, which not only possess unique advantages but also retain the benefits of previously identified bifidobacterial species.